1. Field of the Invention
The present disclosure relates generally to shape memory polymers and, more particularly, shape memory polymer material for use in fixating medical devices to bone.
2. Related Art
Sleeves of shape memory polymer material may be used in fixating medical devices to bone. These sleeves include a central through hole and are placed on a medical device, such as an internal fixation device. After the sleeve is placed on the device, the device is inserted into a bone and energy is then provided to the sleeve causing the sleeve to shrink axially and expand radially. This radial expansion and axial shrinkage of the sleeve allows the sleeve to engage both the device and the inner wall of the bone, thereby fixating the device to the bone.
However, it has been noticed, especially when the energy provided to the sleeve is in the form of a heat source that is placed within the through hole of the sleeve, that the through hole expands, or relaxes away from heat source and the device. This may result in inefficient heating of the sleeve, and thereby incomplete or uneven expansion of the sleeve, and device failure due to insufficient fixation of the device to the bone.